LATEST NEWS FROM WASHINGTON.

Published: September 12, 1862

WASHINGTON, Thursday -- 11:30 P.M.

The tenor of advices from the Potomac, to-day, has been to augment the estimates of yeserday, in regard to the enemy's force there. Their number are placed at from ten thousand to one hundred thousand men, under Gens. R.E. and FITZHUGH LEE, MAGRUDER WALKER, ANDERSON, JACKSON, LONGSTREET and A.P. HILL; and a reporter just in from Frederick puts them still higher.

Gen. LEE's proclamation is regarded as politic arm mischievous.

The reporter above mentioned says that the force at Frederick, when he left, was preparing to march on Hagerstown. He heard a Colonel order his command to be in readiness for that expedition.

Large rebel forces were continually crossing the Potomac. He saw numerous pieces of artillery, generally marked U.S., at Frederick.

There has been a great rush to enlist in the rebel army. The room where names were received was besieged with applicants.